Local Area Networks, or LAN's, are presently used to connect computers, printers, terminals, and other devices that benefit from interconnectivity within a facility, e.g. a home, office or business environment. LAN's are used to share information between users, to share devices such as printers, to enable point-of-sale transactions, and to share connectivity to the Internet.
LAN's are most commonly found in places of business, particularly office buildings. LAN's allow workers to communicate with each other, share files and information, and to share peripherals such as printers and scanners. LAN's are also common in the retail environment, enabling credit card processing and inventory tracking at the point-of-sale.
Traditional LAN's are implemented with a wired network protocol such as Ethernet or AppleTalk®. The wired network backbone is physically brought to, and a connection dropped at, each location that a worker or peripheral must access the network. Peripherals or computers then simply plug into the wired jacks that are installed in each such location.
As can be imagined, the installation of these wired networks to each jack can be time-consuming and expensive. And, once the wired network is installed, reconfigurations to the work environment are equally difficult and further complicated by the presence of the existing wired network.
Because of the expense of installing and reconfiguring the wired network, wireless networks are increasing in popularity. In particular, wireless networking is one of the technologies that is increasing the popularity of in-home networks. Installing traditional wired networks in the home environment proves to be more expensive than in the office environment because walls and ceilings in a home are traditionally designed with less accessibility for wiring as compared with walls and ceilings in an office environment. Wireless networks overcome this obstacle by allowing networked computers to wirelessly communicate with each other, creating wireless networking within the home or office.
FIG. 1 shows a typical implementation of a wireless network with wireless access points (100, 102). The access points (100, 102) are wireless transceivers physically connected to the wired LAN. A device with wireless communication capability within the range of the access points (100, 102) can be included in the LAN by wirelessly communicating with the network through an access point (100, 102). FIG. 1 shows the conventional implementation of such a network which has networked devices both wired (110, 112, 120) and networkly (114, 130) connected to the wired network backbone (e.g., 140). This combination is for illustrative purposes and may vary significantly in practical implementation.
FIG. 1 depicts an example of a conventional wireless network in the computing environment. In the home or office environment, the devices on the network could easily and alternatively be entertainment equipment, such as stereos, televisions, VCR's, or speakers. Portable devices (130) could be cameras, phones, or internet appliances.
For example, in FIG. 1, two personal computers (110, 112) are networked together in a traditional wired network. A peripheral (120), such as a printer, is connected directly to the network, giving both personal computers (110, 112) equal visibility to the peripheral (120).
The center of the wired network backbone is the network hub (140). This hub manages all of the network traffic, coordinating messages between all of the devices on the network. It is also responsible for managing each device's connection to the internet (160).
The access points (100, 102) are conventional wireless transceivers in that they connect through a wire directly to the network backbone and the network hub (140). The wireless coverage area of each device having wireless communications capability is defined by the circle around that device. Personal computer (114) is within range of access point (102), i.e., the access point (102) is within the transmission range of the computer (114) and vice versa. Communication through the access point (102) provides the computer (114) with network connectivity to the other personal computers (110, 112), to peripheral (120), and to the internet (160), through the network hub (140). The wireless communication circuitry built into personal computer (114) is not specifically illustrated and is essentially the same as the known circuitry in the access points (100, 102).
When application programs running on the personal computer (114) send messages to the other devices on the network or to the internet (160), those programs do not need knowledge of the wireless network. Application programs are those programs running under the operating system which provide features and services to the user. If the application programs are using an internet protocol such as TCP/IP running over the network, the same TCP/IP protocol can run over the wireless network. Low-level drivers in the personal computer (114) implement all network traffic over the wireless network, as opposed to low-level drivers in personal computers (110, 112) that implement all network traffic over the wired connections.
Portable device (130) establishes a similar connection to the network through access point (100) and network hub (140). The circle of wireless coverage around portable device (130) is smaller than the other coverage areas, indicating a lower-power wireless transmitter suitable for implementation in such a portable device (130). Implementation of the wireless circuitry in the portable device (130) is essentially the same as the circuitry found in the access points (100, 102) and other devices (e.g., 114), except for the smaller size and lower transmission power.
Application programs running on the portable device (130) also do not need to know about the wireless network if running an internet protocol such as TCP/IP. The portable device (130) simply needs drivers capable of interfacing to the wireless network circuitry, e.g. access points (100, 102). If the wireless communication of portable device (130) was disabled and a wired connection was formed directly to network hub (140), the application programs would work the same.
During normal operation, portable device (130) may fall into an area that allows wireless communication with both access points (100, 102) at the same time. In this scenario, the networking software determines which access point to use, or whether both access points should be used, during wireless communication. It is also possible for portable device (130) to be within the range of wireless communication with three or more access points simultaneously.
Wireless networks such as that illustrated in FIG. 1 have the advantages of being easier to build and reconfigure. Once the wireless access points (100, 102) are installed and connected to the wired network (140), computers (114) and peripherals with wireless capability can be placed or moved anywhere in the coverage area of the access points (100, 102).
Small entirety wireless LAN's can also be built without the use of such access points if all the networked devices are kept within radio frequency (“RF”) range of each other. However, this requires relatively powerful and expensive wireless transceivers in networked device or necessarily limits the size of the area over which the LAN is deployed. The wireless connection is typically a low power RF connection that only covers a 150-foot radius. Many wireless networks use RF in the ISM band, and many commercial wireless networks employ the IEEE802.11 or OpenAir protocols in the 2.4 GHz band. There are many other protocols that are running over many other frequency bands, and many more on the way.
Thus, significant drawbacks to this wireless network implementation include the relatively high cost and size of the RF circuitry required to communicate from one side of a home to the other. This is not so significant problem for desktop computers or printers in which the necessary RF transceiver can be deployed with relative ease. However, it becomes an important issue with handheld Personal Digital Assistants (PDA's), cellular telephones, digital cameras, and other portable devices (130) that benefit from connection to the wireless network.
Therefore, in order to avoid severe limitations on the movement of portable devices within the LAN, additional access points must be added to insure complete coverage of the desired area. The addition of each further access point requires wired connections to be added to furnish the communication link between that access point and the network. This obviously complicates the installation of the network.
Consequently, there is a need in the art for an implementation of an access point that extends the wireless coverage into areas that allow wireless communication with portable devices that otherwise would be out of range without requiring the addition of a wired connection to that access point.